Generally, an air brake system is designed to generate braking force by using the expansion force of compressed air, and it is generally used for trucks and buses which use an air suspension system.
In a conventional technology of the air brake, the compressed air used for generating braking force is supplied to a load sensing valve through an air bellows. Accordingly, when the air bellows is damaged such that it leaks air, the air pressure supplied to a brake chamber is reduced, deteriorating the braking force.